advent-of-code

commit a84967f32c1bac4613bb244d9536697308424c80
parent ac53b953ffdc622dce5c6079768ef9aaf91b9329
Author: finwo <finwo@pm.me>
Date:   Sun, 28 Dec 2025 10:26:23 +0100

Completed 2025/07

Diffstat:
A
2025/07/example.txt
 | 
16
++++++++++++++++
A
2025/07/index.js
 | 
70
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 86 insertions(+), 0 deletions(-)
diff --git a/2025/07/example.txt b/2025/07/example.txt
@@ -0,0 +1,16 @@
+.......S.......
+...............
+.......^.......
+...............
+......^.^......
+...............
+.....^.^.^.....
+...............
+....^.^...^....
+...............
+...^.^...^.^...
+...............
+..^...^.....^..
+...............
+.^.^.^.^.^...^.
+...............
diff --git a/2025/07/index.js b/2025/07/index.js
@@ -0,0 +1,70 @@
+#!/usr/bin/env node
+
+const fs = require('node:fs');
+
+String.prototype.splice = function (start, deleteCount, ...newElements) {
+  return this.slice(0, start) + `${(newElements||[]).join('')}` + this.slice(start + deleteCount);
+}
+
+const input = fs
+  .readFileSync('input', 'utf-8')
+  .split('\r\n').join('\n')
+  .split('\r').join('\n')
+  .split('\n')
+  .filter(e => e)
+
+// Copy & turn into character array
+const part1map = [
+  ...input.map(line => line.split(''))
+];
+
+// Copy & turn into character array
+const part2map = [
+  ...input.map(line => line
+    .split('')
+    .map(char => char === 'S' ? 1 : 0)
+  )
+];
+
+let totalSplits = 0;
+
+for(let lineIdx = 1 ; lineIdx < part1map.length ; lineIdx++) {
+  for(let charIdx = 0 ; charIdx < part1map[lineIdx].length ; charIdx++) {
+
+    switch(`${part1map[lineIdx-1][charIdx]}${part1map[lineIdx][charIdx]}`) {
+      case 'S.':
+      case '|.':
+      case '||':
+        part1map[lineIdx][charIdx]  = '|';
+        part2map[lineIdx][charIdx] += part2map[lineIdx-1][charIdx];
+        break;
+      case '|^':
+        part1map[lineIdx][charIdx-1] = '|';
+        part1map[lineIdx][charIdx+1] = '|';
+        part2map[lineIdx][charIdx-1] += part2map[lineIdx-1][charIdx];
+        part2map[lineIdx][charIdx+1] += part2map[lineIdx-1][charIdx];
+        totalSplits++;
+        break;
+      case '^.':
+      case '.^':
+      case '.|':
+      case '..':
+        // Intentionally empty
+        break;
+      default:
+        throw new Error(`Unhandled case: ${part1map[lineIdx-1][charIdx]}${part1map[lineIdx][charIdx]}`);
+    }
+
+  }
+}
+
+const part1 = totalSplits;
+console.log(`${part1map.map(line => line.join('')).join('\n')}`);
+console.log(`${part2map.map(line => line.map(n => n.toString(36)).join('')).join('\n')}`);
+
+const timelines = part2map.slice(-1)[0].reduce((r,a)=>r+a,0);
+const part2     = timelines;
+
+process.stdout.write(`\n\n`);
+process.stdout.write(`------[ Part 1: ${part1} ]------\n`);
+process.stdout.write(`------[ Part 2: ${part2} ]------\n`);